Sadly,
this is the best picture I can find of the aerial that was our
biggest seller during the 1960s, but there's a much better one
of the similar X17/9K in 'Antique Aerials. The 'X' was the patented
'Antex' band I array. The competing Telefusion 'X' aerial was
merely a dipole and reflector, but the 'Antex' had the active
element at the top rear, and was not a yagi derivative. The signal
nulls were at right angles to the transmitter rather than to the
rear. The '15' indicated a five-element band III section. The
band I and band III sections were linked with a loose length of
twin feeder. When assembling the aerial in the dark (a common
occurrence in the lead-up to Christmas), it was all too easy to
trap the twin feeder in the jaws of the mast clamp, resulting
in a very snowy BBC picture. A swivel arrangement, allowing separate
alignment and even different polarities, physically connected
the two halves of the array. The band III section had no reflector,
the active element being next to the band I section. The ends
of the band III active element were bent at 45 degrees so that
they didn't foul the 'X'. How on earth the boffins at Antiference
ever got this design to work I don't know. Just as a camel is
a horse designed by a committee, this thing looked like an aerial
designed by a camel. But it did work, and it worked well. Anti-ghosting
performance on both bands was far better than the 'single dipole
plus five' array.

The
'9' referred to the chimney lashing kit. The chimney bracket was
an incredibly fiddly, intricate thing, but the design allowed
it to hug the chimney, giving a secure fixing even on uneven masonry.
The 'K' was the swan-neck mast, only 1 inch diameter but very
strong. The whole thing stood up to gales remarkably well, considering
how unwieldy it was. The only weak points were corrosion problems
at the swivel joint and the mast clamp. I suppose we were more
aware of this than most, since we operated in a coalfield area
where it was considered everyone's bounden duty to burn as much
fossil fuel as possible, and the corrosive smog at roof level
was appalling. The X15/9K had a retail price of 116/-, or £5.80,
in 1963. That was almost half a week's wages, as far as I can
remember. A high price to pay for an aerial that received only
two channels of black and white 405 line television!